Arsenal rediscovered their Premier League form on Saturday with a convincing 3-0 victory over Newcastle United at the Emirates Stadium.
Portsmouth ended a run of six successive league defeats when they won 3-0 at Everton while Hull City's flying start ended emphatically when they were thrashed 5-0 at home by Wigan Athletic.
Chelsea face Tottenham Hotspur on Sunday, when Liverpool are in action at Aston Villa, while champions Manchester United take a break after playing in the European Super Cup on Friday.
In Saturday's other games, West Ham United beat Blackburn Rovers 4-1, Middlesbrough beat Stoke City 2-1 and Bolton Wanderers' game against West Bromwich Albion finished goalless.
Arsenal were poor when losing at Fulham last week but were always in control on home soil.
A Charles N'Zogbia handball enabled Robin van Persie to put them ahead with an 18th-minute penalty and the Dutchman got his second five minutes before halftime when he ended a flowing move with a searing shot into the roof of the net.
Another fluid passing movement ended with Denilson tucking in the third.
FA Cup winners Portsmouth last tasted a league victory against West Ham on April 8 and started the new season with two defeats, albeit against Chelsea and Manchester United.
They began well on Saturday though when Jermain Defoe turned well to put them ahead after 11 minutes and a rare effort by defender Glen Johnson made it 2-0 by halftime.
David James saved a Yakubu Aiyegbeni penalty early in the second half and Portsmouth finished with a flourish when a Defoe chip came down off the bar and just over the line, though Crouch was on hand to make doubly sure.
"We played a new system (using wingbacks), the players have worked hard on it all week and that result should give them a lot of belief," Portsmouth manager Harry Redknapp told Sky Sports News.
"I've been wanting to do it for a long time, we've got the personnel to do it with pace at the back and two attacking fullbacks."
Hull began their first season in the top flight with a win and a draw but were thumped by a Wigan team who started with two defeats.
An early own goal, a breakaway by Antonio Valencia and, after the break, two for Amr Zaki and one for Emile Heskey in the second half did the damage.
"It was a harsh reality check," said Hull coach Phil Brown. "If I said we looked a decent side today I'd be a foolish man.
"We had a lot of chances and missed them all while Wigan had five shots on target and scored five."